Kaku and Jabra are actually a bit surprising. I guess it's because Jabra was the one losing ground going from Lucci rival to Kaku's rival, so he get's left behind
it's just a pattern for characters close in strength, with the slightly stronger 1 getting the 1 cm advantage.
You can only use it in that vague manner to point out which is the stronger character in that pair, and that he's not by much.
But come on, let's drop the "coincidence" bit. Oda picked these for all of these characters, it can't be a coincidence.